Multiple tapdisk2 processes may use the same parent disk images (later used to

detect sharable memory pages). This patch establishes unique id for each disk
image opened by tapdisk2, and stores it in shared memory region, thus making it
available to the remaining tapdisk2s.

Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>

2 files changed, 8 insertions, 4 deletions

diff --git a/tools/blktap2/drivers/tapdisk-image.c b/tools/blktap2/drivers/tapdisk-image.c
index 6da7f48bd8..400c467583 100644
--- a/tools/blktap2/drivers/tapdisk-image.c
+++ b/tools/blktap2/drivers/tapdisk-image.c
@@ -28,6 +28,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <memshr.h>
 
 #include "tapdisk-image.h"
 #include "tapdisk-driver.h"
@@ -52,10 +53,11 @@ tapdisk_image_allocate(char *file, int type, int storage,
 		return NULL;
 	}
 
-	image->type    = type;
-	image->flags   = flags;
-	image->storage = storage;
-	image->private = private;
+	image->type      = type;
+	image->flags     = flags;
+	image->storage   = storage;
+	image->private   = private;
+    image->memshr_id = memshr_vbd_image_get(file);
 	INIT_LIST_HEAD(&image->next);
 
 	return image;
@@ -69,6 +71,7 @@ tapdisk_image_free(td_image_t *image)
 
 	list_del(&image->next);
 
+    memshr_vbd_image_put(image->memshr_id);
 	free(image->name);
 	tapdisk_driver_free(image->driver);
 	free(image);
diff --git a/tools/blktap2/drivers/tapdisk-image.h b/tools/blktap2/drivers/tapdisk-image.h
index 8779dff8b7..33b1b851c3 100644
--- a/tools/blktap2/drivers/tapdisk-image.h
+++ b/tools/blktap2/drivers/tapdisk-image.h
@@ -34,6 +34,7 @@
 struct td_image_handle {
 	int                          type;
 	char                        *name;
+    uint16_t                     memshr_id;
 
 	td_flag_t                    flags;
 	int                          storage;